.cf:after {
    content: '';
    clear: both;
    display: table;
}

.fl {
    float: left;
}

.fr {
    float: right;
}

.flex-v {
    display: flex;
    flex-direction: column;
}

html,
body,
#root {
    height: 100%;
}

.fullscreen {
    width: 100%;
    height: 100%;
}

.bg-video {
    display: block;
    flex: 1;
    overflow: hidden;
}

.bg-video video {
    width: 100%;
    height: 100%;
    object-fit: fill;
}

.nav {
    position: relative;
    z-index: 1;
    height: 48px;
    line-height: 48px;
    background-color: #fff;
    border-bottom: 1px solid #dfdfdf;
    padding-left: 48px;
    padding-right: 48px;
    box-shadow: rgba(0, 0, 0, 0.156863) 0px 3px 10px, rgba(0, 0, 0, 0.227451) 0px 3px 10px
}

.logo {
    width: 36px;
    height: 36px;
    margin-top: 6px;
    border-radius: 50%;
}

.menu {
    float: right;
    margin: 0;
    list-style: none;
}

.menu-item {
    float: left;
    padding: 0 18px;
    cursor: pointer;
    background-color: #fff;
    transition: all .3s ease-in-out;
}

.menu-item:hover {
    background-color: #eee;
}

.mask {
    position: absolute;
    left: 0;
    top: 0;
    z-index: 2;
    height: 100%;
    width: 100%;
    background: black;
    opacity: 0.6;
}

.down-icon {
    position: absolute;
    z-index: 5;
    margin-left: 650px;
    margin-top: 550px;
    font-size: 50px;
    color: white;
}
